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Why can't my GK-700rb support the low E?

Discussion in 'Amps and Cabs [BG]' started by Woodboy, Dec 8, 2003.

  1. Woodboy


    Jun 9, 2003
    St. Louis, MO
    I am running my GK-700rb thru a 4-ohm Ampeg BXT-410 cabinet. It should be putting out 380 watts. I can get a good sound with my bass up to a moderate volume level. Once I get into the "feel it as well as hear it" realm, the low E string breaks up and starts to distort (fart) before the other strings do. I am assuming there just isn't enough current to adequately control all 4 speakers at such a low wavelength. It would seem that the amp would have to have an iron grip on those speakers to pump out 41 Hz. cleanly. Some TalkBassers have stated the opinion that 350-400 watts is plenty. It sure doesn't seem to be working for me. Maybe GK's watts are "generous" or maybe it is something arcane like damping factor or solid-state distortion........
  2. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Endorsing Artist: Black Diamond & SuperSensitive strings
    Can you describe the settings you're using with the gains and EQ's when the problem comes up?

    That would help a lot in suggesting how to improve the sound.
  3. Both Ampegs and 410s are not very capable of hitting 41Hz. In other words: most 410s can't hit 41Hz, and Ampeg's designs don't bother with those lower registers either. Ampeg's tone is more in the 100-200 Hz region.
  4. I have to agree with Joris, My Gk 700rb sounds great even on a five string running through 2 GK cabs 1(2x10) 1 1x15. These cabs are heanily ported and basically designed for this amp. I can usually make a room start to buzz before the speakers do. However that same amp and an Ampeg 4x10 at my pratice space sounds exactly like what you are describing. And if said pratice space wasn't up 3 flights of stairs I would bring my cabs with me.

    BTW mess around with the 4 string 5 string switch and the contour control they create a lot of boom in some settings.
  5. JonB


    May 27, 2003
    I'm not familiar with the GK. Does it have speakon output? If so, you might want try installing a speakon connector in the cab. That way, all the current gets to the speaker.
    I just had the situation you describe with an Ampeg V4 head and EA cab. The speakon connector made a huge difference. Of course, the v4 is tube and the GK is transistor, so it may not have as much effect. Anyway, it wouldn't cost much to try this before you give up on the 410.
  6. Sounds to me like your preamp gain is too high. Try lowering that and raising the actual amp volume.
  7. Woodboy


    Jun 9, 2003
    St. Louis, MO
    Thanks, guys for the replies. My settings are: volume 2 o'clock, contour 12 o'clock, presence 9 o'clock, treble 11 o'clock, hi-mid 12 o'clock, low-mid 1 o'clock, bass 1 o'clock, boost 10 o'clock, woofer 3-4 o'clock. Crazy Phil, you might be on to something there. I am never able to get the input clip light to come on to set the threshold, so I may have the gain set too high. JonB, I use the Speakons and they made a big difference. Gallient Knight, I tried the GK cabinets and you are right, they held together with this head very well. The sound was a little dry and hollow to my tastes though (YMMV!). An interesting note is that I tried my 700rb with an Eden 410 when I was shopping around. It sounded exactly the way my Ampeg is sounding with this head, only more so. The sales guy had me plug into the same Eden cab with a higher wattage Eden head and the problem cleared up. The sound was just massive. I was only in the market for a cab at that time, so I didn't consider the Eden head. It should be noted that I play only fingerstyle with TI Flats. Reproducing clean tone with fingerstyle seems a different matter than slapping. Slapping is quick duration and percussive and the notes aren't around long enough to tell if they are deep and round. I like to hear slapping, it just isn't part of the music I play, which is old school blues and r&b.
  8. jawzzz


    May 23, 2003
    Denver Colorado
    I would also have to say it is the head. I have a BXT 410hl4 and it handles a low "E" perferctly. I don't even get distortion with a low "B". The BXT series is much better at the low end than the classic series and should have no problem reproducing a low "E". This with a Crown CE 1000 either bridged @ 4 ohms for 1100 watts or just in stereo giving it 450 watts @ 4 ohms. Try messsing with the settings on your head.

    The only other possibillity is that one or more of your speakers are starting to go out.
  9. lamarjones

    lamarjones Supporting Member

    Aug 27, 2002
    Raleigh, NC
    Get the head checked. My 700rb rocks my EA VL210 and my Eden 410 xlt, your should do the same.
  10. rumblinbass


    Aug 22, 2003
    Wimberley, TX
    My GK rig ROCKS! I have a 700RB run into a parallel combo 410RBH and SWR GOlliath III jr. (both 8 ohm cabs). I couldn't be happier. I'm getting plenty of volume - even when competing with the loudest drummer I have ever jammed with and 2 Marshall 100W halfs. In fact, I tried this rig for the first time the last time we practiced and they told me to turn down...that was a first.

    There could be several reasons why you are having trouble getting those lower frequencies. I rarely ever hit an open E. Most tens have trouble getting that low...I think the open E is down into the low 30's (Hz). Maybe eq settings :confused: ? I know that cutting mids cuts your volume. What kind of pickups are in your bass? What kind of bass is it?

    Also, keep in mind that in order to pump lower frequencies you need more power. But 380W should be plenty.
  11. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    Unless the cab has a driver failing, it is VERY unlikely that it is the cab. They are rated -3 db at 45 hz and I think they even rate them -10 db at 35 hz. They are also 600 RMS and 1200 program. An RB 700 is not going to make them puke.

    It's hard to know what a particular person's version of "loud" really is, but the most likely case is the amp is clipping.

    Plus power is only part of the equation. Often, 400 watts RMS is plenty. In your case, maybe not.

    Those cabs are rated 99 db sensitivity. Compared to a Eden XLT (106 db), Goliath III (105) or even Aguilar 410 (104), that is fairly power hungry. In other words, any of the above mentioned cabs would be noticeably louder when played with the same GK head.

    You need twice the power for a 3 db gain in spl. (For reference 10 db is considered "twice" as loud) So in your case, the Ampeg driven at 600W would have the same perceived loudness as an XLT or Goliath III driven at only 150 watts. Or inversely, the XLT or Goliath under the same power would be just less than twice as loud as the Ampeg.

    For reference, Acme cabinets, which carry the reputation as the most inefficient bass cabs on the planet, (I am not sure that they actually are) are rated at 96 db 1W/1M.

    Of course each cabinet handles different frequencies differently and demands different EQ settings, etc., so the efficiency issue is sort of a moving target, but you get the idea that for your cab, you may need more than you might for another cab.

    All that said, GK heads may indeed be generously rated. I never liked them in the 80s when they became the thing, so I haven't had any interest in them since.
  12. Chasarms, sounds an awful lot like an Ampeg employee to me:eek: Clearly it must be the ampeg cabinet and not our head;)

    Seriously, Try making these adjustments to your settings. Volume at 12 oclock, Boost at 12 oclock, Woofer to whatever your desired loudness is. The clip light does not measure the preamp gain, it only monitors the signal from your bass. If the clip light is coming on, you would need to either turn the volume knob on your bass down or press in the -14dB pad. The volume knob on the amp will have no effect on the clip light.
  13. rumblinbass


    Aug 22, 2003
    Wimberley, TX
    I practiced last night with my band and paid a little more attention to the volume when I hit an open E. I have to say that I am more impressed than ever before, I didn't lose any volume!

    Probably your cabinet.:rolleyes:
  14. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Endorsing Artist: Black Diamond & SuperSensitive strings
    Daniel points out something unusual about the GK head. On many amps (SWR, Eden, Ampeg, for examples), the clip light responds to settings in gain and EQ, looking at the total gain from a few different sections.

    The GK clip light, in comparison, measures only the input signal level. Very few basses exceed this level, so it will rarely come on...my G&L L-1000 passive bass has such a hot pickup that it actually can trigger the light if played hard.

    With the GK, it seems like setting the input gain optimally is less of a concern than with other amps, and has as much to do with the nature of growl as anything.

    For example, I recently brought my SWR SM-400S to a blues jam, set up the input gain for each player and then watched them exceed that level once the band got going so that the clip light flashed lots, or even stayed on for one heavy-handed player. With the GK, it'd be less of a concern...and differences in player volume could be managed more by the boost and woofer/master knobs.

    One other thing...watch the "String 4/5" button. If it's pressed in, the lows are boosted quite a bit, which could make a much bigger demand on the amp's power output.
  15. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Setting Contour at 12:00 is a pretty large bass boost! Try rolling it back (this will give you more midrange) and I'll bet the farting decreases. The "feel it" EQ range is really low mids, it's not the fundamental you're after anyway.
  16. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Endorsing Artist: Black Diamond & SuperSensitive strings
    Actually, the GK manual for the 700RB says that for the contour knob, the bass boost is only +2db at 50hz.

    It does, however cut up to -10db at 500hz, which is a prime frequency for having the bass cut through the band. So I'd agree that backing off the contour control will help with perceived loudness, but doesn't change the bass level all that much at 1/2 way up. From the GK manual:

    Contour +2db@50Hz / -10db@500Hz / +3db@7kHz
  17. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    Hardly. I don't think I would point out what a juice hog that cab is if I worked for Ampeg. I do live in St. Louis though, so that's a fair enough presumption.

    I have played that cabinet before. It sounds great, but it just is not a very loud box. I really think he may be pushing the amp harder than he thinks.

    He may want to drop that cabinet and get a nice GK 103 db rated cab to match his head. (Now you can accuse me of being a GK employee :) )

    Seriously, that head is plenty of juice in the right speaker box.
  18. Daniel - When are we going to get some spec data, or some free samples of the new line of cabinets. Trip had a contract with Talk bass that every supporting member got a free cabinet or amp of their choice for Christmas.

    Private mail me and I will send you my address for delivery.
  19. Metal Mitch

    Metal Mitch

    Jul 14, 2003
  20. Wes Whitmore

    Wes Whitmore

    Mar 10, 2003
    Columbus, OH
    My bass made the biggest difference in my low end extension. I thought it was my cab, so I got a Big ben 18, and it didn't help. Then I changed the bass, and I have all the extension in the world, even with just my 2x10. Maybe verify that while you are there. See if your bass sounds like you want it to on other cabs.

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